U.S. patent application number 13/540761 was filed with the patent office on 2013-01-31 for antenna apparatus.
This patent application is currently assigned to OLYMPUS MEDICAL SYSTEMS CORP.. The applicant listed for this patent is Masatoshi HOMAN. Invention is credited to Masatoshi HOMAN.
Application Number | 20130027267 13/540761 |
Document ID | / |
Family ID | 46171567 |
Filed Date | 2013-01-31 |
United States Patent
Application |
20130027267 |
Kind Code |
A1 |
HOMAN; Masatoshi |
January 31, 2013 |
ANTENNA APPARATUS
Abstract
An antenna apparatus includes: first and second receiving
antennas disposed on a plane at equal distances from a reference
point and face each other with the reference point therebetween;
third and fourth receiving antennas disposed on the plane, a
gravity center of the third and fourth receiving antennas being an
equal distance from the reference point, a straight line connecting
the gravity centers of the third and fourth receiving antennas is
at 90 degrees with respect to a straight line connecting gravity
centers of the first and second receiving antennas; fifth, sixth,
seventh and eighth receiving antennas disposed on the plane, having
gravity centers on straight lines different from each other and
rotated by an angle of 45 degrees from the straight line connecting
the gravity centers of the first and second receiving antennas and
the straight line connecting the gravity centers of the third and
fourth receiving antennas, respectively.
Inventors: |
HOMAN; Masatoshi; (Tokyo,
JP) |
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Applicant: |
Name |
City |
State |
Country |
Type |
HOMAN; Masatoshi |
Tokyo |
|
JP |
|
|
Assignee: |
OLYMPUS MEDICAL SYSTEMS
CORP.
Tokyo
JP
|
Family ID: |
46171567 |
Appl. No.: |
13/540761 |
Filed: |
July 3, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2011/074354 |
Oct 21, 2011 |
|
|
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13540761 |
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Current U.S.
Class: |
343/810 ;
343/879; 343/893 |
Current CPC
Class: |
A61B 5/07 20130101; A61B
1/00016 20130101; H01Q 9/285 20130101; A61B 1/041 20130101; H01Q
21/24 20130101; H01Q 1/38 20130101; H01Q 1/273 20130101 |
Class at
Publication: |
343/810 ;
343/893; 343/879 |
International
Class: |
H01Q 21/00 20060101
H01Q021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 29, 2010 |
JP |
2010-265757 |
Claims
1. An antenna apparatus comprising: a first receiving antenna and a
second receiving antenna respectively disposed at positions on a
plane which are in an equal distance from a reference point and
face each other with the reference point therebetween; a third
receiving antenna and a fourth receiving antenna disposed at
positions on the plane, a gravity center of the third receiving
antenna and a gravity center of the fourth receiving antenna being
in an equal distance from the reference point on the plane, a
straight line connecting the gravity centers of the third receiving
antenna and the fourth receiving antenna being at an angle of 90
degrees with respect to a straight line connecting a gravity center
of the first receiving antenna and a gravity center of the second
receiving antenna; a fifth receiving antenna, a sixth receiving
antenna, a seventh receiving antenna, and an eighth receiving
antenna disposed respectively at positions on the plane, gravity
centers of the fifth to eighth receiving antennas being on straight
lines different from each other, which are rotated by an angle of
45 degrees from the straight line connecting the gravity centers of
the first receiving antenna and the second receiving antenna and
the straight line connecting the gravity centers of the third
receiving antenna and the gravity center of the fourth receiving
antenna, respectively, wherein each of the first to the eighth
receiving antennas is formed such that two conductive wires
symmetrically extend to left and right sides to be in a straight
line and have a same length, a direction of the conductive wires of
the first receiving antenna is parallel to a direction of the
conductive wires of the second receiving antenna, a direction of
the conductive wires of the third receiving antenna is parallel to
a direction of the conductive wires of the fourth receiving antenna
and orthogonal to the direction of the conductive wires of the
first receiving antenna and the direction of the conductive wires
of the second receiving antenna, a direction of the conductive
wires of the fifth receiving antenna is parallel to a direction of
the conductive wires of the sixth receiving antenna, and a
direction of the conductive wires of the seventh receiving antenna
is parallel to a direction of the conductive wires of the eighth
receiving antenna and orthogonal to the direction of the conductive
wires of the fifth receiving antenna and the direction of the
conductive wires of the sixth receiving antenna.
2. The antenna apparatus according to claim 1, wherein the first to
fourth receiving antennas are disposed respectively at positions
which are in an equal distance from the reference point within the
plane.
3. The antenna apparatus according to claim 1, wherein the third
and fourth receiving antennas are in an equal distance from the
reference point and are disposed, with respect to the reference
point, closer to outer peripheries of the plane than the first and
second receiving antennas.
4. The antenna apparatus according to claim 1, wherein the first to
eighth receiving antennas are balanced antennas exhibiting a larger
loss in cross polarization than in main polarization.
5. The antenna apparatus according to claim 1, wherein the first to
eighth receiving antennas are dipole antennas.
6. The antenna apparatus according to claim 1, wherein the first to
eighth receiving antennas are provided with first to eighth active
circuits, respectively.
7. The antenna apparatus according to claim 1, wherein the first to
eighth receiving antennas are disposed on one plate unit.
8. The antenna apparatus according to claim 7, wherein the third
and fourth receiving antennas are disposed on outer peripheries of
the plate unit.
9. The antenna apparatus according to claim 8, further comprising:
first to eighth transmission lines to transmit and receive a signal
to and from the first to eighth receiving antennas, respectively,
and wherein the first to eighth transmission lines gather at an end
portion of the plate unit.
10. The antenna apparatus according to claim 7, wherein the plate
unit includes a positioning unit that positions the antenna
apparatus with respect to a target object to which the antenna
apparatus is mounted.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of PCT international
application Ser. No. PCT/JP2011/074354 filed on Oct. 21, 2011 which
designates the United States, incorporated herein by reference, and
which claims the benefit of priority from Japanese Patent
Applications No. 2010-265757, filed on Nov. 29, 2010, incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a receiving antenna
apparatus that receives a radio signal transmitted from a capsule
endoscope inside of a subject.
[0004] 2. Description of the Related Art
[0005] Conventionally, in the field of an endoscope, a capsule
endoscope with a built-in imaging function and a radio
communication function, which are provided in a capsule-shaped
casing formed to a size that can be introduced into the gut of a
subject such as a patient, is known. The capsule endoscope is first
swallowed from the mouth of the subject and then it moves in the
inside of the subject such as the gut by peristaltic movement and
the like. Then, it sequentially captures images of the inside of
the subject to generate image data, and sequentially transmits the
image data.
[0006] The image data thus transmitted from the capsule endoscope
by wireless transmission is received by a receiving apparatus
through a receiving antenna provided outside the subject. The
receiving apparatus stores the image data received through the
receiving antenna in a built-in memory.
[0007] The subject can freely act during a period until the capsule
endoscope is excreted after the capsule endoscope is swallowed, by
carrying the receiving apparatus that has a radio communication
function and a memory function. After the examination, a
practitioner such as a doctor puts the image data accumulated in
the memory of the receiving apparatus in an image display apparatus
so that images of the inside of the subject which correspond to the
images obtained by the capsule endoscope, that is, the internal
organs' images are displayed on a display of the image display
apparatus. The practitioner observes the images of the internal
organs and the like displayed on the display, and diagnoses the
subject.
[0008] In receiving the radio signal transmitted from the capsule
endoscope, a typical receiving apparatus has a plurality of
receiving antennas arranged in a dispersed manner outside the
subject, selects one antenna with the strongest received strength,
and receives the radio signal by the selected antenna. For example,
there is a known receiving apparatus in which reception switching
among a plurality of antennas placed outside a subject is performed
and which detects the position of a capsule endoscope in the
subject that is the source of a radio signal based on the field
strength received by each antenna (See Japanese Patent Application
Laid-open Publication No. 2003-000608).
SUMMARY OF THE INVENTION
[0009] An antenna apparatus according to an aspect of the present
invention includes: a first receiving antenna and a second
receiving antenna respectively disposed at positions on a plane
which are in an equal distance from a reference point and face each
other with the reference point therebetween; a third receiving
antenna and a fourth receiving antenna disposed at positions on the
plane, a gravity center of the third receiving antenna and a
gravity center of the fourth receiving antenna being in an equal
distance from the reference point on the plane, a straight line
connecting the gravity centers of the third receiving antenna and
the fourth receiving antenna being at an angle of 90 degrees with
respect to a straight line connecting a gravity center of the first
receiving antenna and a gravity center of the second receiving
antenna; a fifth receiving antenna, a sixth receiving antenna, a
seventh receiving antenna, and an eighth receiving antenna disposed
respectively at positions on the plane, gravity centers of the
fifth to eighth receiving antennas being on straight lines
different from each other, which are rotated by an angle of 45
degrees from the straight line connecting the gravity centers of
the first receiving antenna and the second receiving antenna and
the straight line connecting the gravity centers of the third
receiving antenna and the gravity center of the fourth receiving
antenna, respectively, wherein each of the first to the eighth
receiving antennas is formed such that two conductive wires
symmetrically extend to left and right sides to be in a straight
line and have a same length, a direction of the conductive wires of
the first receiving antenna is parallel to a direction of the
conductive wires of the second receiving antenna, a direction of
the conductive wires of the third receiving antenna is parallel to
a direction of the conductive wires of the fourth receiving antenna
and orthogonal to the direction of the conductive wires of the
first receiving antenna and the direction of the conductive wires
of the second receiving antenna, a direction of the conductive
wires of the fifth receiving antenna is parallel to a direction of
the conductive wires of the sixth receiving antenna, and a
direction of the conductive wires of the seventh receiving antenna
is parallel to a direction of the conductive wires of the eighth
receiving antenna and orthogonal to the direction of the conductive
wires of the fifth receiving antenna and the direction of the
conductive wires of the sixth receiving antenna.
[0010] The above and other features, advantages and technical and
industrial significance of this invention will be better understood
by reading the following detailed description of presently
preferred embodiments of the invention, when considered in
connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic diagram that illustrates an outline of
a configuration of a capsule endoscope system provided with an
antenna apparatus according to an embodiment of the present
invention;
[0012] FIG. 2 is a plan view that illustrates a schematic
configuration of the antenna apparatus according to the embodiment
of the present invention;
[0013] FIG. 3 is a block diagram that illustrates a schematic
configuration of a first receiving antenna illustrated in FIG.
2;
[0014] FIG. 4 is a block diagram that illustrates a schematic
configuration of a receiving apparatus illustrated in FIG. 1;
[0015] FIG. 5 is a plan view that illustrates a schematic
configuration of an antenna apparatus according to Modification 1
of the embodiment of the present invention;
[0016] FIG. 6 is a plan view that illustrates a schematic
configuration of an antenna apparatus according to Modification 2
of the embodiment of the present invention;
[0017] FIG. 7 is a plan view that illustrates a schematic
configuration of an antenna apparatus according to Modification 3
of the embodiment of the present invention;
[0018] FIG. 8 is a plan view that illustrates a schematic
configuration of an antenna apparatus according to Modification 4
of the embodiment of the present invention; and
[0019] FIG. 9 is a plan view that illustrates a schematic
configuration of an antenna apparatus according to Modification 5
of the embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] Hereinbelow, an antenna apparatus according to an embodiment
of the present invention is described referring to the drawings. In
the following description, a capsule endoscope system including a
capsule endoscope, which is introduced into the inside of a subject
to capture in-vivo images of the subject, is presented as an
example of an antenna apparatus according the present invention.
However, the present invention is not limited by this
embodiment.
[0021] As illustrated in FIG. 1, a capsule endoscope system 1
includes a capsule endoscope 3 that captures an in-vivo image of a
subject 2, an antenna apparatus 4 that receives a radio signal
transmitted from the capsule endoscope 3 introduced in the subject
2, a receiving apparatus 5 that performs predetermined processing
on the radio signal input from the antenna apparatus 4 and stores
the processing result, and an image display apparatus 6 that
displays an image corresponding to image data of the inside of the
subject 2 captured by the capsule endoscope 3.
[0022] The capsule endoscope 3 has an imaging function to capture
an image of the inside of the subject 2, and a radio communication
function to transmit image data obtained by capturing an image of
the inside of the subject 2 to the receiving apparatus 5. The
capsule endoscope 3 is swallowed by the subject 2 so that it passes
through the esophagus of the subject 2 and moves in the body cavity
of the subject by peristaltic movement of the lumen of the gut. The
capsule endoscope 3 sequentially captures images of the body cavity
of the subject 2 at intervals of a minute time, for example, an
interval of 0.5 seconds while moving in the body cavity, and
sequentially generates and transmits image data of the captured
images of the inside of the subject 2 to the receiving apparatus 5.
In this case, the capsule endoscope 3 generates a transmission
signal, which includes the image data and received-field-strength
detection data including position information (beacon) etc. which
makes received field strength easy to be detected, and transmits a
radio signal obtained by modulating the generated transmission
signal to the receiving apparatus 5 by wireless transmission.
[0023] The antenna apparatus 4 outputs the radio signal, received
from the capsule endoscope 3, to the receiving apparatus 5 through
an antenna cable 51. The antenna apparatus 4 is fixed to the
subject 2 with a belt or the like during the examination.
[0024] The receiving apparatus 5 acquires the radio signal, which
is transmitted from the capsule endoscope 3 by wireless
transmission, through the antenna apparatus 4 and the antenna cable
51. The receiving apparatus 5 acquires the image data of the inside
of the subject 2 based on the radio signal received from the
capsule endoscope 3. The receiving apparatus 5 stores
received-field-strength information and time information which
indicates a time point in association with the received image data.
The receiving apparatus 5 is carried by the subject 2 while the
capsule endoscope 3 is capturing images, that is, during a period
from when the endoscope is introduced from the mount of the subject
2 and to when the endoscope passes through the gut and is finally
excreted out of the subject 2. After the examination using the
capsule endoscope 3 ends, the receiving apparatus 5 is removed from
the subject 2 and is then connected to the image display apparatus
6 so that information on the image, data etc. received from the
capsule endoscope 3 can be transmitted.
[0025] The image display apparatus 6 is configured by a work
station or a personal computer including a display such as a liquid
crystal display. The image display apparatus 6 displays an image
corresponding to the image data in the subject 2 acquired by the
receiving apparatus 5. A cradle 6a that reads the image data from
the memory of the receiving apparatus 5 and an operation input
devices 6b such as a keyboard and a mouse are connected to the
image display apparatus 6. The cradle 6a acquires image data, the
received-field-strength information associated with the image data,
time information, and relevant information such as identification
information of the capsule endoscope 3, from the memory of the
receiving apparatus 5 when the receiving apparatus 5 is mounted,
and transmits the acquired various information to the image display
apparatus 6. The operation input device 6b accepts the input from
the user. As a result, the user observes living body parts in the
subject 2, for example, the esophagus, the stomach, the small
intestine, and the large intestine, and makes a diagnosis on the
subject 2 while operating the operation input device 6b and viewing
the images of the inside of the subject 2 which are sequentially
displayed by the image display apparatus 6.
[0026] Next, details of a configuration of the antenna apparatus 4
illustrated in FIG. 2 are described. FIG. 2 is a plan view that
illustrates a schematic configuration of the antenna apparatus 4.
As illustrated in FIG. 2, the antenna apparatus 4 includes a plate
unit 40, a first receiving antenna 41, a second receiving antenna
42, a third receiving antenna 43, a fourth receiving antenna 44, a
fifth receiving antenna 45, a sixth receiving antenna 46, a seventh
receiving antenna 47, an eighth receiving antenna 48, and a
connector 49. The first to eighth receiving antennas 41 to 48 are
provided on one plate unit 40.
[0027] The plate unit 40 is formed of a sheet-like flexible
substrate. The principal surface of the plate unit 40 is
substantially octagonal. The plate unit 40 is formed to a size that
can cover the entire surface of the abdomen of the subject 2, for
example, 200 mm in length.times.200 mm in width. The plate unit 40
has an opening 40a. The opening 40a is formed such that the center
is coincident with a reference point O.sub.1 of the plate unit 40.
The opening 40a functions as a positioning unit which positions the
antenna apparatus with respect to the subject 2 when the antenna
apparatus is attached to the subject 2. As a result, when the plate
unit 40 is attached to the subject 2, the antenna apparatus 4 can
be easily positioned. The opening 40a may be formed using a
transparent member, for example, a transparent vinyl sheet, etc.
Incidentally, the principal surface of the plate unit 40 does not
necessarily have a substantial octagonal shape, but may have a
rectangular shape, etc.
[0028] The first receiving antenna 41 and the second receiving
antenna 42 are disposed at positions which face each another with
the reference point O.sub.1 therebetween. The first receiving
antenna 41 and the second receiving antenna 42 are disposed at
positions which are in an equal distance from the reference point
O.sub.1. Specifically, the first receiving antenna 41 and the
second receiving antenna 42 are disposed respectively at the
positions on the plate unit 40 which are in a distance of r.sub.1
from the reference point O.sub.1. As for the first receiving
antenna 41 and the second receiving antenna 42, an element 41a and
an element 42a thereof are formed on the plate unit 40 as printed
circuits. The first receiving antenna 41 and the second receiving
antenna 42 include an active circuit 41b and an active circuit 42b
connected to the element 41a and the element 42a, respectively. The
active circuits 41b and 42b are both formed on the plate unit 40 as
planar circuits, respectively. The active circuits 41b and 42b
perform impedance matching respectively for the first receiving
antenna 41 and the second receiving antenna 42, performs
amplification processing including amplification and attenuation on
a received radio signal, and performs balanced-to-unbalanced
transformation on the received radio signal. The first receiving
antenna 41 and the second receiving antenna 42 are connected to the
connector 49 provided in the plate unit 40 via planar transmission
lines (striplines), respectively.
[0029] The third receiving antenna 43 and the fourth receiving
antenna 44 are disposed at positions which are in-plane rotated
about the reference point O.sub.1 by 90 degrees respectively from
the first receiving antenna 41 and the second receiving antenna 42.
The third receiving antenna 43 and the fourth receiving antenna 44
are disposed respectively at positions on the plate unit 40 which
are in a distance of r.sub.1 from the reference point O.sub.1. As
for the third receiving antenna 43 and the fourth receiving antenna
44, an element 43a and an element 44a thereof are both formed on
the plate unit 40 as printed circuits. The third receiving antenna
43 and the fourth receiving antenna 44 include an active circuit
43b and an active circuit 44b connected to the element 43a and the
element 44a, respectively. The third receiving antenna 43 and the
fourth receiving antenna 44 are connected to the connector 49 via
planar transmission lines, respectively.
[0030] The fifth receiving antenna 45 and the sixth receiving
antenna 46 are disposed at positions which are in-plane rotated
about the reference point O.sub.1 by 45 degrees respectively from
the first receiving antenna 41 and the second receiving antenna 42.
The fifth receiving antenna 45 and the sixth receiving antenna 46
are disposed to be closer to outer peripheries of the plane than
the first receiving antenna 41 and the second receiving antenna 42
within the plane. Specifically, the fifth receiving antenna 45 and
the sixth receiving antenna 46 are disposed respectively at
positions on the plate unit 40 which are each in a distance of
r.sub.2 (r.sub.1<r.sub.2) from the reference point O.sub.1. As
for the fifth receiving antenna 45 and the sixth receiving antenna
46, an element 45a and an element 46a thereof are both formed on
the plate unit 40 as printed circuits. The fifth receiving antenna
45 and the sixth receiving antenna 46 include an active circuit 45b
and an active circuit 46b connected to the element 45a and the
element 46a, respectively. The fifth receiving antenna 45 and the
sixth receiving antenna 46 are connected to the connector 49 via
planar transmission lines, respectively.
[0031] The seventh receiving antenna 47 and the eighth receiving
antenna 48 are disposed at positions which are in-plane rotated
about the reference point O.sub.1 by 90 degrees respectively from
the fifth receiving antenna 45 and the sixth receiving antenna 46.
The seventh receiving antenna 47 and the eighth receiving antenna
48 are disposed to be closer to outer peripheries of the plane than
the first receiving antenna 41 and the second receiving antenna 42
within the plane. Specifically, the seventh receiving antenna 47
and the eighth receiving antenna 48 are disposed respectively at
positions on the plate unit 40 which are each in a distance of
r.sub.2 (r.sub.1<r.sub.2) from the reference point O.sub.1. As
for the seventh receiving antenna 47 and the eighth receiving
antenna 48, an element 47a and an element 48a thereof are both
formed on the plate unit 40 as printed circuits. The seventh
receiving antenna 47 and the eighth receiving antenna 48 include an
active circuit 47b and an active circuit 48b connected to the
element 47a and the element 48a, respectively. The seventh
receiving antenna 47 and the eighth receiving antenna 48 are
connected to the connector 49 via planar transmission lines,
respectively.
[0032] Here, details of the configuration of the first receiving
antenna 41 illustrated in FIG. 2 are described. FIG. 3 is a block
diagram that illustrates the configuration of the first receiving
antenna.
[0033] As illustrated in FIG. 3, the first receiving antenna 41 is
configured by a balanced antenna. Specifically, the first receiving
antenna 41 is configured such that the element 41a is a dipole
antenna having two linear conductive wires. In the first receiving
antenna 41, the two linear conductive wires of the element 41a are
in a straight line, symmetrically extend to left and right sides,
and have the same length. Because of this configuration, the first
receiving antenna 41 exhibits large loss in cross polarization
compared with main polarization. Since the second to eighth
receiving antennas 42 to 48 which are described above have the same
configuration as the first receiving antenna 41, the description
thereof is not repeated. In the present embodiment, the number of
receiving antennas is not necessarily construed to be limited to 8,
but may be more than 8.
[0034] With the configuration described above, the antenna
apparatus 4 can receive all polarizations transmitted by the
capsule endoscope 3 regardless of the orientation and position of
the capsule endoscope 3 in the subject 2.
[0035] Next, details of the configuration of the receiving
apparatus illustrated in FIG. 1 are described. FIG. 4 is a block
diagram that illustrates the configuration of the receiving
apparatus illustrated in FIG. 1. In the following description, when
any one of the first to eighth receiving antennas 41 to 48 is
described, the first receiving antenna 41 (the element 41a, the
active circuit 41b) is representatively described.
[0036] As illustrated in FIG. 4, the receiving apparatus 5 includes
the antenna cable 51 connected to each of the first to eighth
receiving antennas 41 to 48 via the connector 49 of the antenna
apparatus 4, a cable connector 52 to which the antenna cable 51 is
connected, an antenna changeover selection switch unit 53 that
selectively switches among the first to eighth receiving antennas
41 to 48, a receiving circuit 54 that performs processing such as
modulation on a radio signal received through any one of the first
to eighth receiving antennas 41 to 48 which is selected by the
antenna changeover selection switch unit 53, a signal processing
circuit 55 that performs signal processing of extracting image data
and the like from the radio signal output from the receiving
circuit 54, a received-field-strength detector 56 that detects a
received field strength based on the strength of the radio signal
output from the receiving circuit 54, an antenna power supply
changeover selector 57 that switches among the first to eighth
receiving antennas 41 to 48 and supplies power to any one of the
first to eighth receiving antennas 41 to 48, a display unit 58 that
displays an image corresponding to the image data received from the
capsule endoscope 3, a storage unit 59 that stores various
information including the image data received from the capsule
endoscope 3, an I/F unit 60 that mutually transmits and receives
data to and from the image display apparatus 6 via the cradle 6a, a
power supply unit 61 that supplies power to all the units of the
receiving apparatus, and a control unit 62 that controls the
operation of the receiving apparatus 5.
[0037] The antenna cable 51 is configured by a coaxial cable. The
antenna cable 51 has core wires, the number of which corresponds to
the number of the first to eighth receiving antennas 41 to 48. For
example, the antenna cable 51 has eight core wires. The antenna
cable 51 transmits the radio signals received by each of the first
to eighth receiving antennas 41 to 48 to the receiving apparatus 5,
and transmits the power supplied from the receiving apparatus 5 to
each of the first to eighth receiving antennas 41 to 48.
[0038] The antenna cable 51 is connected to the cable connector 52
in a detachable manner. The cable connector 52 is electrically
connected to the antenna changeover selection switch unit 53 and
the antenna power supply changeover selector 57.
[0039] The antenna changeover selection switch unit 53 is
configured by a mechanical switch, a semiconductor switch, or the
like. The antenna changeover selection switch unit 53 is
electrically connected to each of the first to eighth receiving
antennas 41 to 48 via a capacitor C1. When a switch signal S1 used
to switch the receiving antenna which receives the radio signal is
input from the control unit 62, the antenna changeover selection
switch unit 53, for example, selects the first receiving antenna 41
as instructed by the switch signal S1 and outputs the received
radio signal through the selected first receiving antenna 41 to the
receiving circuit 54. The capacitance of each of capacitors
respectively connected to the first to eighth receiving antennas 41
to 48 is equal to the capacitance of the capacitor C1.
[0040] The receiving circuit 54 performs predetermined processing
such as demodulation or amplification on the radio signal received
through the first receiving antenna 41 selected by the antenna
changeover selection switch unit 53, and outputs the processed
signal to each of the signal processing circuit 55 and the
received-field-strength detector 56.
[0041] The signal processing circuit 55 extracts the image data
from the radio signal input from the receiving circuit 54, performs
predetermined processing, for example, various kinds of image
processing and/or A/D conversion processing on the extracted image
data, and outputs the resultant signal to the control unit 62.
[0042] The received-field-strength detector 56 detects the received
field strength corresponding to the strength of the radio signal
input from the receiving circuit 54, and outputs a
received-field-strength signal (RSSI: Received Signal Strength
Indicator) corresponding to the detected received field strength to
the control unit 62.
[0043] The antenna power supply changeover selector 57 is
electrically connected to each of the first to eighth receiving
antennas 41 to 48 via a coil L1. The antenna power supply
changeover selector 57 supplies the power to the first receiving
antenna 41 selected by the antenna changeover selection switch unit
53 through the antenna cable 51. The antenna power supply
changeover selector 57 includes a power supply changeover selection
switch unit 571 and an abnormality detector 572. The electrical
characteristic of each of coils respectively connected to the first
to eighth receiving antennas 41 to 48 is equal to the
characteristic of the coil L1.
[0044] The power supply changeover selection switch unit 571 is
configured by a mechanical switch, a semiconductor switch, or the
like. When a selection signal S2 used to select the receiving
antenna which is to be supplied with power is input from the
control unit 62, the power supply changeover selection switch unit
571 selects, for example, the first receiving antenna 41 as
instructed by the selection signal S2, and supplies power only to
the selected first receiving antenna 41.
[0045] The abnormality detector 572 outputs, to the control unit
62, an abnormality signal indicating an event that abnormality is
caused in the first receiving antenna 41 to which power is
supplied, when abnormality occurs in the first receiving antenna 41
to which power is supplied. Specifically, the abnormality detector
572 detects a disconnection abnormality or a short-circuit
abnormality in the first receiving antenna 41 based on the voltage
supplied to the first receiving antenna 41 selected by the power
supply changeover selection switch unit 571, and outputs the
detection result to the control unit 62.
[0046] The display unit 58 is configured by using a display panel
composed of liquid crystal, organic Electro Luminescence (EL), or
the like. The display unit 58 displays various information such as
images corresponding to the image data captured by the capsule
endoscope 3, operation status of the receiving apparatus 5, patient
information of the subject 2, and examination data and time.
[0047] The storage unit 59 is configured by a semiconductor memory
such as flash memory and Random Access Memory (RAM) provided
fixedly in the receiving apparatus 5. The storage unit 59 stores
the image data captured by the capsule endoscope 3 and/or various
kinds of information associated with the image data, for example,
position information of the capsule endoscope 3, orientation
information of the capsule endoscope 3, received-field-strength
information, and identification information used to identify the
receiving antenna that has received the radio signal. The storage
unit 59 stores various kinds of programs to be executed by the
receiving apparatus 5. The storage unit 59 may have a function as a
recording medium interface which stores information in an external
recording medium such as a memory card, and reads information
stored in the recording medium.
[0048] The I/F unit 60 functions as a communication interface and
mutually transmits and receives data to and from the image display
apparatus 6 through the cradle 6a.
[0049] The power supply unit 61 is configured by a battery
detachable from the receiving apparatus 5 and a switch unit which
performs switching between ON state and OFF state. The power supply
unit 61 supplies necessary driving power to each unit of the
receiving apparatus 5 when it is in ON state, and stops supplying
the driving power to each unit of the receiving apparatus 5 when it
is in OFF state.
[0050] The control unit 62 is configured by a Central Processing
Unit (CPU) or the like. The control unit 62 reads the programs out
of the storage unit 59 and executes the programs, and collectively
controls the operation of the receiving apparatus 5 by giving
instructions or transmitting data to the respective units which
constitute the receiving apparatus 5. The control unit 62 includes
a selection controller 621 and an abnormality information adding
unit 622.
[0051] The selection controller 621 performs control of selecting
the receiving antenna to receive the radio signal transmitted from
the capsule endoscope 3 and supplying power only to the selected
receiving antenna. Specifically, the selection controller 621
performs control of selecting the receiving antenna to receive the
radio signal transmitted from the capsule endoscope 3 and supplying
power only to the selected receiving antenna, based on the received
electric field strengths of the first to eighth receiving antennas
41 to 48 which are detected by the received-field-strength detector
56. For example, the selection controller 621 drives the antenna
changeover selection switch unit 53 at every predetermined timing,
for example, every 100 msec to sequentially select the receiving
antennas to receive the radio signal transmitted from any one of
the first to eighth receiving antennas 41 to 48, and repeats such a
process until the received electric field strength detected by the
received-field-strength detector 56 reaches a predetermined
value.
[0052] When the abnormality detector 572 detects abnormality caused
in any one of the first to eighth receiving antennas 41 to 48, the
abnormality information adding unit 622 adds abnormality
information indicating that abnormality is caused in any one of the
first to eighth receiving antennas 41 to 48 to the radio signals
which are respectively received by the first to eighth receiving
antennas 41 to 48, and outputs the resultant signal to the storage
unit 59. Specifically, the abnormality information adding unit 622
adds a flag indicating the abnormality information to the image
data which has been subjected to the signal processing performed by
the signal processing circuit 55, for each of the radio signals
respectively received by the first to eighth receiving antennas 41
to 48, and outputs the resultant signal to the storage unit 59.
[0053] Antenna switch and selection processing performed by the
selection controller 621 in the antenna apparatus 4 and the
receiving apparatus 5 configured in this way is described
below.
[0054] First, along with the activation of the receiving apparatus
5, the selection controller 621 performs control of selecting any
one of the first to eighth receiving antennas 41 to 48 by
activating the antenna changeover selection switch unit 53 at every
predetermined timing, for example, every 100 msec and supplying
power only to the receiving antenna selected by the antenna
changeover selection switch unit 53. In this case, the abnormality
detector 572 detects each of the disconnection abnormality and the
short-circuit abnormality in each of the first to eighth receiving
antennas 41 to 48 sequentially selected by the selection controller
621, and outputs the detection result to the control unit 62. The
control unit 62 determines whether abnormality is caused in any one
of the first to eighth receiving antennas 41 to 48 based on the
detection result of the abnormality detector 572. The control unit
62 may output the detection result with respect to the first to
eighth receiving antennas 41 to 48 to the display unit 58. In this
way, the user can check whether there is abnormality caused in any
one of the first to eighth receiving antennas 41 to 48. As a
result, it is possible to prevent the examination result of the
subject 2 from becoming useless, which may occur because it is
difficult to acquire highly precise and accurate image data due to
the abnormality of the receiving antenna.
[0055] After pre-processing performed along with the activation of
the receiving apparatus 5, the capsule endoscope 3 is introduced
into the subject 2. Along with the introduction, the selection
controller 621 performs control of sequentially switching and
selecting the receiving antenna to receive the radio signal
transmitted from the capsule endoscope 3 at every predetermined
timing and supplying power only to the selected receiving
antenna.
[0056] Next, the selection controller 621 selects the receiving
antenna where the received electric field strength detected by the
received-field-strength detector 56 is strongest among the first to
eighth receiving antennas 41 to 48, and supplies power only to the
selected receiving antenna.
[0057] After that, the selection controller 621 performs control of
switching among the first to eighth receiving antennas 41 to 48 to
select one receiving antenna to receive the radio signal
transmitted from the capsule endoscope 3 at every predetermined
timing until the capsule endoscope 3 is excreted from the inside of
the subject 2, and supplying power only to the selected receiving
antenna. In this case, the abnormality detector 572 detects each of
the disconnection abnormality and the short-circuit abnormality
caused in one of the first to eighth receiving antennas 41 to 48
selected by the selection controller 621, and outputs the detection
result to the control unit 62. The control unit 62 determines
whether abnormality is caused in any of the first to eighth
receiving antennas 41 to 48 based on the detection result of the
abnormality detector 572.
[0058] When abnormality is caused in any one of the first to eighth
receiving antennas 41 to 48, the abnormality information adding
unit 622 adds abnormality information indicating that abnormality
is caused in any of the first to eighth receiving antennas 41 to 48
to the image data, which has been received by any one of the first
to eighth receiving antennas 41 to 48 and has been subjected to the
signal processing performed by the signal processing circuit 55,
and stores the resultant in the storage unit 59. As a result, when
the image of the inside of the subject 2 captured by the capsule
endoscope 3 is displayed by the image display apparatus 6, the
image display apparatus 6 displays the abnormal information added
to the image data. Accordingly, it is possible to determine whether
abnormality was caused in the first to eighth receiving antennas 41
to 48 at certain time points, which enables to determine whether
the image data can be used for inspection.
[0059] According to the embodiment of the present invention
described above, the antenna apparatus includes the first receiving
antenna 41 and the second receiving antenna 42 disposed at
positions on a plane, which face each other with the reference
point O.sub.1 therebetween and are in an equal distance from the
reference point O.sub.1, the third receiving antenna 43 and the
fourth receiving antenna 44 disposed at positions which are
in-plane rotated about the reference point O.sub.1 by 90 degrees
from the first receiving antenna 41 and the second receiving
antenna 42, respectively, the fifth receiving antenna 45 and the
sixth receiving antenna 46 disposed at positions which are closer
to outer peripheries of the plane than the first receiving antenna
41 and the second receiving antenna 42 and which are in-plane
rotated about the reference point O.sub.1 by 45 degrees from the
first receiving antenna 41 and the second receiving antenna 42,
respectively, and the seventh receiving antenna 47 and the eighth
receiving antenna 48 disposed at positions which are in-plane
rotated about the reference point O.sub.1 by 90 degrees from the
fifth receiving antenna 45 and the sixth receiving antenna 46,
respectively. As a result, the radio signal transmitted from the
capsule endoscope 3 introduced in the subject 2 is precisely
detected and the position of the capsule endoscope 3 can be
accurately detected.
[0060] Furthermore, according to the embodiment of the present
invention, the selection controller 621 performs control of
selecting one receiving antenna to receive the radio signal
transmitted from the outside from among the first to eighth
receiving antennas 41 to 48 and supplying power only to the
selected receiving antenna. As a result, even when a plurality of
active antennas, each being provided with an active circuit, is
used, power consumption may be reduced and influence of the
interference among the receiving antennas also may be reduced.
[0061] Furthermore, according to the embodiment of the present
invention, the abnormality detector 572 detects each of the
disconnection abnormality and the short-circuit abnormality and
outputs the detection result to the control unit 62. As a result,
the control unit 62 can easily determine whether there is
abnormality caused in any one of the first to eighth receiving
antennas 41 to 48 at the time of activation of the capsule
endoscope 3 and the receiving apparatus 5, or during the
examination of the subject 2.
[0062] Moreover, according to the embodiment of the present
invention, the antenna cable which connects the antenna apparatus 4
and the receiving apparatus 5 can be integrated in one cable,
resulting in a reduction in the failure of the antenna cable.
[0063] Moreover, according to the embodiment of the present
invention, since the first to eighth receiving antennas 41 to 48
are provided with the active circuits 41b to 48b, respectively, the
radio signal transmitted from the capsule endoscope 3 can be
received without having to closely attach the first to eighth
receiving antennas 41 to 48 to the subject 2.
[0064] Yet furthermore, according to the embodiment of the present
invention, when radiation pattern of the radio signal transmitted
by the capsule endoscope 3 and the shape of a transmitting antenna
of the capsule endoscope 3 which transmits the radio signal in a
polarization direction are known beforehand, the received field
strength is measured by all the first to eighth receiving antennas
41 to 48, and the position and direction of the capsule endoscope 3
are detected while taking balance among the received field
strengths of the first to eighth receiving antennas 41 to 48. With
this method, the position of the capsule endoscope 3 in the subject
2 can be easily estimated.
[0065] According to the embodiment of the present invention, the
capsule endoscope 3 modulates the image data acquired from the
subject 2 and transmits the result as the radio signal. Thus, by
receiving and demodulating the radio signal using the receiving
antenna with the strongest received field strength among the first
to eighth receiving antennas 41 to 48, the image data can be
reliably restored.
[0066] In the embodiment of the present invention, the third
receiving antenna 43 and the fourth receiving antenna 44 are
disposed at positions which are in-plane rotated about the
reference point O.sub.1 by 90 degrees from the first receiving
antenna 41 and the second receiving antenna 42, respectively, the
fifth receiving antenna 45 and the sixth receiving antenna 46 are
disposed at positions which are in-plane rotated about the
reference point O.sub.1 by 45 degrees from the first receiving
antenna 41 and the second receiving antenna 42, respectively, and
the seventh receiving antenna 47 and the eighth receiving antenna
48 are disposed at positions which are in-plane rotated about the
reference point O.sub.1 by 90 degrees from the fifth receiving
antenna 45 and the sixth receiving antenna 46, respectively.
However, the positions to arrange the fifth to eighth receiving
antennas 45 to 48 may be changed. Specifically, the third receiving
antenna 43 and the fourth receiving antenna 44 may be disposed at
such positions on the plate unit 40 that the gravity center of the
third receiving antenna 43 and the gravity center of the fourth
receiving antenna 44 are in an equal distance from the reference
point O.sub.1 and a straight line which connects the gravity center
of the third receiving antenna 43 and the gravity center of the
fourth receiving antenna 44 is at an angle of 90 degrees with
respect to a straight line which connects the gravity center of the
first receiving antenna 41 and the gravity center of the second
receiving antenna 42. Moreover, the fifth receiving antenna 45 and
the eighth receiving antenna 48 may be disposed at such positions
on the plate unit 40 that the gravity center of the fifth receiving
antenna 45 and the gravity center of the eighth receiving antenna
48 are arranged in straight lines, respectively, which are
different from each other and each of which is at an angle of 45
degrees with respect to both a straight line which connects the
gravity center of the first receiving antenna 41 and the gravity
center of the second receiving antenna 42 and a straight line which
connects the gravity center of the third receiving antenna 43 and
the gravity center of the fourth receiving antenna 44.
[0067] Modification 1
[0068] In the embodiment described above, the positions at which
the first to eighth receiving antennas 41 to 48 are arranged may be
changed. FIG. 5 is a plan view that illustrates a schematic
configuration of an antenna apparatus according to Modification 1
of the embodiment of the present invention. As illustrated in FIG.
5, in an antenna apparatus 70, first to eighth receiving antennas
41 to 48 are disposed at positions which are rotated about the
reference point O.sub.1 by 45 degrees respectively from the
arrangement positions in the above described embodiment. With this
configuration, the same effects as the above-described embodiment
can be achieved.
[0069] Modification 2
[0070] FIG. 6 is a plan view that illustrates a schematic
configuration of an antenna apparatus according to Modification 2
of the embodiment of the present invention. As illustrated in FIG.
6, in an antenna apparatus 80, an element 41a of a first receiving
antenna 41 and an element 42a of a second receiving antenna 42 are
arranged to face each other with a reference point O.sub.1
therebetween on a straight line passing the reference point
O.sub.1. Moreover, in the antenna apparatus 80, an element 43a of a
third receiving antenna 43 and an element 44a of a fourth receiving
antenna 44 are arranged to face each other with the reference point
O.sub.1 therebetween on a straight line passing the reference point
O.sub.1. With this configuration, the same effects as the
above-described embodiment can be achieved.
[0071] Modification 3
[0072] FIG. 7 is a plan view that illustrates a schematic
configuration of an antenna apparatus according to Modification 3
of the embodiment of the present invention. As illustrated in FIG.
7, in an antenna apparatus 90, an element 45a of a fifth receiving
antenna 45 and an element 46a of a sixth receiving antenna 46 are
arranged to face each other with a reference point O.sub.1
therebetween in a straight line passing the reference point
O.sub.1. Moreover, in the antenna apparatus 90, an element 47a of a
seventh receiving antenna 47 and an element 48a of an eighth
receiving antenna 48 are arranged to face each other with a
reference point O.sub.1 therebetween in a straight line passing the
reference point O.sub.1. With this configuration, the same effects
as the above-described embodiment can be achieved.
[0073] Modification 4
[0074] FIG. 8 is a plan view that illustrates a schematic
configuration of an antenna apparatus according to Modification 4
of the embodiment of the present invention.
[0075] As illustrated in FIG. 8, an antenna apparatus 100 includes:
a first receiving antenna 41 and a second receiving antenna 42
disposed at positions on a plane, which face each other with a
reference point O.sub.1 therebetween and are in a distance of r11
from the reference point O.sub.1; a third receiving antenna 43 and
a fourth receiving antenna 44 disposed at positions which are
in-plane rotated about the reference point O.sub.1 by 90 degrees
from a straight line which connects the gravity center of the first
receiving antenna 41 and the gravity center of the second receiving
antenna 42; a fifth receiving antenna 45 and a sixth receiving
antenna 46 disposed at positions which are closer to outer
peripheries of the plane than the first receiving antenna 41 and
the second receiving antenna 42, an extending direction of each of
the fifth and sixth receiving antennas 45 and 46 being a straight
line having an angle of 45 degrees with respect to a straight line
which connects the gravity center of the first receiving antenna 41
and the gravity center of the second receiving antenna 42, the
gravity centers of the fifth and sixth receiving antennas 45 and 46
being disposed at positions within the plane; and a seventh
receiving antenna 47 and an eighth receiving antenna 48 disposed at
positions closer to the outer peripheries of the plane than the
third receiving antenna 43 and the fourth receiving antenna 44, an
extending direction of the seventh receiving antenna 47 and the
eighth receiving antenna 48 being a straight line having an angle
of 45 degrees with respect to a straight line which connects the
gravity center of the third receiving antenna 43 and the gravity
center of the fourth receiving antenna 44, the gravity centers of
the seventh receiving antenna 47 and the eighth receiving antenna
48 being disposed at positions within the plane.
[0076] Specifically, the third receiving antenna 43 and the fourth
receiving antenna 44 are disposed respectively at positions on a
plate unit 40 which are in an equal distance of r.sub.12
(r.sub.11<r.sub.12) from the reference point O.sub.1, and are
more away from each other than those of the first receiving antenna
41 and the second receiving antenna 42. Moreover, the fifth to
eighth receiving antennas 45 to 48 are disposed respectively at
positions on the plate unit 40 which are in an equal distance of
r.sub.13 (r.sub.12<r.sub.13) from the reference point, and are
more away from each other than those of the third receiving antenna
43 and the fourth receiving antenna 44. With this configuration,
the plate unit 40 of the receiving antenna apparatus 100 may be
decreased in length L1 and increased in width L2.
[0077] According to Modification 4 of the embodiment described
above, the same effect as the above-described embodiment can be
achieved, and the antenna apparatus 100 can be easily attached to
the subject 2.
[0078] According to Modification 4 of the embodiment of the present
invention described above, both of the third receiving antenna 43
and the fourth receiving antenna 44 may be arranged on the outer
periphery of the plate unit 40.
[0079] Modification 5
[0080] In Modification 4 of the embodiment described above, the
distance between the first receiving antenna 41 and the second
receiving antenna 42 and the distance between the third receiving
antenna 43 and the fourth receiving antenna 44 may be changed. FIG.
9 is a plan view that illustrates a schematic configuration of an
antenna apparatus according to Modification 5 of the embodiment of
the present invention. Hereinbelow, the first receiving antenna 41
and the second receiving antenna 42 are described as the third
receiving antenna 43 and the fourth receiving antenna 44, and the
third receiving antenna 43 and the fourth receiving antenna 44 are
described as the first receiving antenna 41 and the second
receiving antenna 42.
[0081] As illustrated in FIG. 9, in a receiving antenna 110, a
first receiving antenna 41 and a second receiving antenna 42 are
disposed respectively at positions on a plate unit 40 which are in
an equal distance of r.sub.11 (r.sub.12<r.sub.11) from a
reference point O.sub.1, are more away from each other than those
of a third receiving antenna 43 and a fourth receiving antenna 44,
and are closer to outer peripheries of the plate unit 40.
Specifically, the first receiving antenna 41 and the second
receiving antenna 42 are disposed such that an element 41a and an
element 42a thereof are both formed on the outer periphery of the
plate unit 40. Moreover, the fifth to eighth receiving antennas 45
to 48 are disposed respectively at positions on the plate unit 40
which are in an equal distance of r.sub.13 (r.sub.12<r.sub.13)
from the reference point O.sub.1, and are more away from each other
than those of the third receiving antenna 43 and the fourth
receiving antenna 44. With this configuration, the receiving
antenna 110 can be configured such that the length L3 of the plate
unit 40 is further reduced compared with the length L1 of
Modification 4 of the embodiment described above (L1>L3) and the
width L4 of the plate unit 40 is increased. For example, as for a
receiving apparatus, the plate unit 40 thereof may have a length L3
of 140 mm and a width L4 of 190 mm.
[0082] According to Modification 5 of the embodiment described
above, the same effect as the above-described embodiment can be
achieved, and the length of the plate unit 40 can be reduced, so
that the antenna apparatus 110 can be easily attached to the
subject 2.
[0083] In Modification 5 of the embodiment of the present invention
described above, the first receiving antenna 41 and the second
receiving antenna 42 may be disposed on the outer peripheries of
the plate unit 40, respectively.
Other Embodiments
[0084] In the embodiment described above, although the active
circuits are connected to the first to eighth receiving antennas 41
to 48, respectively, transformation circuits (balun) which
transform balanced state to unbalanced state may be connected to
the first to eighth receiving antennas 41 to 48, respectively.
[0085] Moreover, although the first to eighth receiving antennas 41
to 48 are configured by dipole antennas in the embodiment described
above, the first to eighth receiving antennas 41 to 48 may be
configured by loop antennas or open type antennas.
[0086] Furthermore, although the abnormality detector 572 detects
the abnormality of the first to eighth receiving antennas 41 to 48
based on voltage in the embodiment described above, the abnormality
of the first to eighth receiving antennas 41 to 48 may be detected
based on current and/or power. Yet furthermore, the abnormality
detector 572 may detect the abnormality of the first to eighth
receiving antennas 41 to 48 based on a combination of voltage,
current, and power.
[0087] In the embodiment described above, the image display
apparatus 6 can acquire in-vivo image data captured by the capsule
endoscope 3 in various ways. For example, in the receiving
apparatus 5, a memory card such as a USB memory and a compact flash
(registered trademark) which can be removed from the receiving
apparatus 5 may be used instead of the built-in storage unit 59. In
this case, after the image data is loaded from the capsule
endoscope 3 to the memory, only the memory is removed from the
receiving apparatus 5, and then the memory may be inserted into a
USB port or the like of the image display apparatus 6 for example.
Furthermore, the image display apparatus 6 may be provided with a
communication function, so that the image data may be acquired from
the receiving apparatus 5 by wired communication or wireless
communication.
[0088] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
* * * * *